5results about How to "Adjustable molecular weight" patented technology

The invention discloses a high-frequency low dielectric loss benzocyclobutene resin and its preparation method and application. The 1,3-position diene, benzocyclobutene group, vinyl compound, initiator and organic solvent are polymerized under the conditions of 5°C to 78°C and then treated to obtain a high-frequency low dielectric loss benzocyclobutene resin. The high-frequency low dielectric loss benzocyclobutene resin prepared by the present invention has excellent thermal stability, mechanical properties and dielectric properties after high-temperature curing. At a frequency of 10 GHz, its dielectric constant (Dk) is 2.35-2.60, dielectric loss (Df) is 0.0004-0.0007, T 5％ The thermal decomposition temperature is 442‑465°C, and the thermal expansion coefficient of the cured resin is 32‑88ppm / °C@50°C. Therefore, it can be used as high-temperature resistant dielectric materials, high-performance composite materials, electronic packaging materials, and aviation materials; it can be used in 5G / 6G high-frequency PCB boards and interlayer packaging of chips, etc.

The application provides a high-refraction cycloolefin copolymer and a preparation method thereof, and has a structure of formula I. The cycloolefin copolymer can obtain a cycloolefin copolymer resin with high thermal stability due to high steric hindrance of the cycloolefin monomer. The refractive index of the cycloolefin copolymer resin is greatly improved due to R3 and R4 on the cycloolefin monomer, and is first broken through to above 1.70, while maintaining high light transmittance of 91.0-96.0%, extremely low water absorption (<0.01%), and a glass transition temperature of 219 DEG C. The application prepares the cycloolefin copolymer resin with high activity, adjustable molecular weight and glass transition temperature by adjusting the reaction conditions. The copolymer resin has high refractive index, high light transmittance, heat resistance, low birefringence and moisture absorption, excellent fluidity, moldability and dimensional stability.

This invention discloses a polymer coating material and its preparation method, as well as its application in artificial graphite anode materials. The polymer is synthesized from monomers, comonomers, and reaction auxiliaries under the action of an initiator. By controlling the amount of reaction auxiliaries added, the molecular weight of the polymer is controllable, and the side functional groups are adjustable. This polymer can uniformly coat the surface of artificial graphite, forming an artificial solid-state electrolyte interface, optimizing the lithium-ion transport path, and constructing a stable protective layer for the artificial graphite anode material. It can effectively improve the initial coulombic efficiency of the artificial graphite anode material, achieving an initial coulombic efficiency ≥91.8%.

The invention provides a polyphenylene ether polyol terminated with an alcohol hydroxyl group and a preparation method thereof. The polyphenylene ether polyol terminated with an alcohol hydroxyl group is prepared by reacting a double-terminated hydroxyl polyphenylene ether with an alkyl carbonate or an epoxide in the presence of an alkaline catalyst, and has alcohol hydroxyl groups at both ends. The molecular weight and degree of polymerization of the polyphenylene ether polyol terminated with an alcohol hydroxyl group are adjustable, and the property is stable. The polyphenylene ether polyol terminated with an alcohol hydroxyl group can be used not only to modify a polymer, but also as an intermediate for preparing a polymer. The addition of the polyphenylene ether polyol terminated with an alcohol hydroxyl group can give the obtained product some unique characteristics of polyphenylene ether, and improve the hardness, heat resistance and other properties of the obtained polymer. At the same time, the preparation method of the polyphenylene ether polyol terminated with an alcohol hydroxyl group is simple, the reaction selectivity is high, the yield is high, the production cost is low, and the application prospect is good.

The present invention provides a method for depolymerizing lignin, depolymerization products and applications, and relates to the field of green utilization of agricultural and forestry waste resources. The present invention adopts a new dual-functional solvent system with the ability to dissolve and degrade lignin, and realizes controllable and efficient depolymerization of industrial lignin. Under suitable depolymerization parameters, industrial lignin raw materials with a molecular weight of 10,000 to 200,000 and a molecular weight distribution of 2 to 5 can be degraded into oligomers with a molecular weight of 400 to 1200 and a molecular weight distribution of 1.2 to 2.0, the yield of the oligomers is 80 to 96%, and the hydroxyl value of the oligomers is 400 to 700 mgKOH / g. The comprehensive performance of the bio-based rigid foam polyurethane prepared from the raw materials is significantly better than that of similar petroleum-based products, and has excellent degradability and cost advantages.